What are the Different Types of Pump Strainers?
Strainers for pump systems primarily function as filters for the liquids or gases going through the system’s piping. While a seemingly simple assignment, many pump applications depend on properly working strainers. For pumps used in any pipeline operation, sediment that may include sand, dirt, or other detritus can build up within the pipes or elsewhere in the system. Whatever the pumping application, strainers for pumps ensure the whole system runs smoothly.
Without strainers, pumps cannot contain debris, contaminating the water or other substances transported through them. Debris can also clog pumps and piping, making the pump work harder or increasing pressure beyond desired limits. While a simple piece of equipment, strainers for pumps are integral for industries that utilize pumping systems to transport fluids. Understanding the different types of strainers helps stakeholders choose the best type of strainer for their specific application.
Types Of Strainers for Pumps
Also known as strainer filters or piping strainers, pump strainers protect equipment and processes from all debris, including loose weld metal, rust, and scaling within a pump system. They utilize a mesh or perforated straining component to mechanically remove solids from fluids and gases flowing through a pipeline. These solids could potentially damage equipment or contaminate the substance as it’s being pumped, leading to unplanned downtime.
For pumps to function best, strainers should be installed within the system before other sensitive equipment like burners, compressors, control valves, loading valves, meters, nozzles, pressure regulators, solenoid valves, steam traps, turbines, and unit heaters, as well as the pumps themselves. Certain types of strainers for pumps work best for specific applications, though commonly, they strain particles between 0.00156 to 1.0 inch (39.624 to 25,400 microns). Now, let’s look at the more commonly used strainers for pumps.
Shaped as a “Y,” these pump strainers are used for applications with fewer solids to be separated from the media being transported. Though they’re often put in places where the need for frequent maintenance is more likely. Best used with substances in gaseous form, these strainers require regular cleaning to reduce the chance of blockage, though they’re sometimes used for fluids with lower solid concentrations. These strainers' bodies usually consist of iron or an iron alloy like steel, with the filtering element made from stainless steel.
Used typically in suction-type systems or pressurized lines, Y-type strainers for pumps increase the efficiency of pipelines. However, their greatest advantage lies in their ability to operate in any position. Often placed where pressures reach over 6000 pounds per square inch (PSI) (421.8417 kg per cm²), Y-type strainers feature two holes with a drainpipe set diagonally to clear and collect debris. Normally these strainers for pumps are used in vertical layouts, with the pipe positioned at a right angle. There’s a greater chance for erosion when placed horizontally, so the strainer should be installed at a right angle or positioned horizontally.
These strainers for pumps work well in pipes that necessitate regular cleaning or filter larger-sized particles. They’re referred to by several different names, including T-type, pot top, inline, or even inline basket strainers. Basket strainers for pumps can withstand pressures up to about 1500 PSI (105.4604 kg per cm²). Featuring a larger straining area, they can store more particles, an advantage over other strainers. For pumps and piping systems, this means less frequent cleaning is necessary.
However, basket strainers only work in parallel pipes and require reinforcement due to their bulkier construction. Fortunately, cleaning and replacing basket strainers is fairly easy, as they have an easily accessible and detachable filtering element for capturing debris. When installed in steam systems, these strainers also feature a steam trap and drain stoppers to collect condensation. A couple of different types of basket strainers for pumps are commonly used.
Used in oil and gas processing, these types of basket strainers for pumps are commonly made from iron and its alloys, with the filtering element made from stainless steel. Different filtering grades are available depending on the application, making them particularly versatile, and their design makes them easier to open for cleaning or simple maintenance. They tend to be used in pumping systems that can be shut down for short periods to enable maintenance, with the filter element’s length allowing less pressure drop and offering greater capacity for holding large particles.
Duplex Strainers & Twin Strainers
These two pump strainers feature dual straining elements that allow flow to alternate between the two baskets. Due to this attribute, these strainers work well for continuous applications where cleaning is difficult during processing. They can do this by switching baskets when one gets too full, making cleaning much easier than with other strainers. They're particularly useful for pumps that operate continuously since cleaning can take place without halting operations.
Both types of strainers use either ball or plug-type valves, which permit fluids to flow from one basket to another. Installed only in piping that’s positioned in parallel, these strainers work well for larger pipelines that need to run continuously and are usually used in piping systems for fuel, oil, or water. Though very similar, duplex and twin strainers aren’t quite the same, with duplex strainers experiencing higher pressure drops and using an internal shared valving. In comparison, twin strainers experience lower pressure drops and use external control valves.
Installed between pipe flanges, temporary strainers for pumps are meant only to be used on a short-term basis. Inexpensive and coming in various styles, temporary strainers should be chosen based on the application for which they’ll be used. Cleaning, maintaining, and replacing temporary strainers normally takes considerably longer than permanent strainers, making their upkeep more intensive.
The three basic types of temporary strainers for pumps are:
- Conical: Also known as witch’s hat strainers due to their shape, these temporary strainers are used for applications that include water treatment and power generation, as well as petroleum and chemical processing.
- Flat disc: Looking something like a tennis racket, it’s shaped like a flat disk with perforated holes covering the pipe’s bore area and offers an inexpensive and easy-to-install option for a temporary pump strainer.
- Truncated conical: This is a basket-style strainer for pumps that temporarily transport gaseous or liquid substances, though it can be used more permanently in certain applications.
Pressure caused by the flowing media tends to distort temporary strainers, which is partly why they’re generally not used for longer periods.
Specialty Strainers for Pumps
There are also several different types of strainers for pumps that serve specific purposes. They’re classified based on the pumping systems, with certain applications requiring these specialty strainers.
Specialty strainers for pumps include those with the following features:
- Jacketed: Featuring housings made from cast iron or other metals, these enhance the stability of the strainer, which helps keep media flowing through the pump system at a higher temperature than that outside the system.
- Large capacity baskets: These can hold larger amounts of debris than other basket strainers, with their design preventing blockage when media flowing through them is denser and stickier; their straining qualities provide for better purification of liquids or gases.
- Magnetic: Featuring magnets, these strainers for pump systems attract iron molecules that can cause the spread of rust internally, keeping them from destroying vital elements within the system.
- Wide differential: Strainers for pumps with heavier wire mesh or welded mesh screens can deal with wider pressure differentials and are much better than other non-specialty strainers at handling higher pressures.
In addition to these, there are also automatic strainers for pumps that can be used for permanent applications. These feature baskets with self-cleaning capabilities ensure an uninterrupted cleaning process that’s controlled manually, by pressure drops to certain levels, or via timers. Typically, they’re made from iron-based alloys, though they can be made from other materials, with the basket made from stainless steel.
Choosing the Right Strainers for Pumps
Hayes Pump Inc. is the largest distributor of municipal, industrial, and commercial pumps throughout the Northeast. We carry a wide range of strainers for pumps for all purposes, including pump strainers made by Viking Pump. For more information about strainers for pumps and which strainer would work best for your specific application, contact the experts at Hayes Pump.